Background: A large number of mothers may not be practicing exclusive breastfeeding in rural Jamaica, although no recent systematic study has been conducted. The impact of knowledge about and attitude toward breastfeeding on the duration of exclusive breastfeeding is also poorly understood. The objective of this study was to gather information about factors that influence exclusive breastfeeding and its duration. Method: A cross-sectional study was conducted in 11 health centers within the parish of Saint Ann, Jamaica. A pretested questionnaire collected information on breastfeeding knowledge and attitudes toward intention to breastfeed and other relevant socio-demographic characteristics. Results: Information was documented for 599 mother-child pairs. The prevalence of breastfeeding initiation was 98.2 percent; of mothers who initiated breastfeeding, 22.2 percent practiced it exclusively (at least 6 months). No difference occurred between exclusive and nonexclusive breastfeeding mothers in terms of knowledge about and attitudes toward breastfeeding. Of potential predictors assessed, the male partner's role as the main source of income for the family was the only significant predictor for exclusive breastfeeding. Women whose male partner was the main source of income for the family were twice as likely to exclusively breastfeed their infants compared with the referent group (mothers as main source of income) (OR = 2.0; 95% CI = 1.4-3.0). In addition, the dominant reason for partial breastfeeding was maternal anxiety that breastmilk alone might not provide sufficient nourishment. Conclusion: The level of exclusive breastfeeding was extremely low at the study site. Formulation of strategies to aggressively promote exclusive breastfeeding practices is urgently needed there. Such interventions should consider involvement of the male partner, especially, with respect to the financial support, as well as alleviating maternal anxiety regarding nutritional adequacy of breastmilk. © 2004 Blackwell Publishing, Inc.